1. Field of the invention
The present invention relates to a control method for the operation modes of an oscillator and the apparatus thereof, more particularly to, an automatic control method for the operation modes of an oscillator and the apparatus thereof.
2. Description of the Related Art
Refer to FIG. 1, FIG. 1 illustrates the conventional logic circuit 10, and said circuit 10 comprising: an oscillator operation mode control circuit 101; an oscillator circuit 102; and an oscillating clock signal 103, wherein said oscillator circuit 102 is for receiving the control signal from said circuit 101, and the connection between said circuit 101 and said circuit 102 is built as an open loop.
FIGS. 1a, 1b, and 1c relates to a diagram for conventional oscillator operation mode control circuit and external oscillating signals, wherein for FIG. 1a, a quartz oscillator is connected onto the oscillator, for FIG. 1b, an external RC network is connected to the oscillator, and for FIG. 1c, an external square wave is inputted to the oscillator directly.
The user providing the desirable oscillator operation mode to said circuit 101, and via said circuit 101 the oscillator operation mode control signal was passed to said oscillator control circuit 102 so as to enable said oscillator 102 to start oscillating correctly and to output said signal 103.
Conventionally, there exists a demand for the multi-mode oscillator to setting the parameter by user to choose the desirable oscillator operation mode, wherein the parameter setting must be restored in the electronic circuit. Hereby we make examples to explain the parameter settings restored in different positions as follows:
If the setting parameters for the oscillator operation mode were restored in the electronic circuit device for which the memory cannot be modified right after manufacturing such as ROM (Read-Only Memory), then under this circumstance the inventory must be kept separately for the products with identical circuit function but merely different in oscillator operation modes, and the user cannot arbitrarily change the operation mode of said oscillator.
If the setting parameters for oscillator operation mode were restored in the EPROM (Erasable Programmable ROM) when the user write the oscillator operation mode into said EPROM and other program codes remain unchanged, then the oscillator operation mode for unpackaged chips is usually changed by the application of the ultraviolet light to erase the information restored in the EPROM and to write new oscillator operation mode into EPROM again; however, if the chips were already packaged then the packages outside the chips must be taken away, then the ultraviolet light is inevitably applied to erase the information in the EPROM. Such a process is a waste of time and not economic.
If the setting parameters for oscillator operation mode were restored in the EEPROM or Flash Memory, the user can burn the program on said memory to modify the setting parameters, however, if there is exceeding quantity of the parameters, then much additional effort will be needed.
If the setting parameters for oscillator operation mode were restored in the register inside the chip, then the users need to know how to choose the desirable setting parameters via the firmware or other approach.
Accordingly, in view of the above drawbacks, it is an imperative that an improved oscillator, particularly a control method for automatically choosing multi-mode oscillator and the apparatus is designed so as to solve the drawbacks as the aforementioned process to set up the parameters. By the disclosures of the present invention, the user can set up the operation mode of an oscillator rather than manually, for which not only the user's inconvenience can be saved but the manufacturing cost can be saved as well.